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NEPA Details


Categorical Exclusion For the City of Memphis T.E. Maxson WWTF Process and Biosolids Upgrades Program

Document Number


Document Type


Project Description

The proposed project consists of the following: GMP 1 - Peri-acetic Acid (PAA) Disinfection Tank and Effluent Piping Structure Upgrades. A new 300-foot by 160-foot concrete peri-acetic acid (PAA) disinfection process will be installed, including hydraulic improvements to connect the new treatment system and new bulk storage and chemical feed facilities to the existing plan infrastructure. PAA storage and feed systems will be procured from the PAA provider. A new plant electrical service will also be constructed. GMP 2 - Headworks Improvements. The plant’s two existing manual coarse screens will be replaced with new 1-inch mechanical coarse screens and washing presses. GMP 3 - Two Secondary Clarifiers, Odor Control Improvements and Fine-Bubble Conversion. Two new 135-foot diameter secondary clarifiers and dedicated return activated sludge (RAS) and scum pump stations, five new bio-trickling filters and associated ductwork will be installed to replace the on-site odor control system, and conversion of the 14 existing aeration basins from coarse to fine-bubble diffusers. GMP 4 - RAS Re-aeration Basin. A new 3.5 million-gallon concrete RAS re-aeration basin will be constructed to aerate the plant RAS prior to blending with the trickling filter effluent. This package will also include a new blower building. GMP 5 - Existing Trickling Filter Upgrades. Six 135-foot diameter trickling filters will be upgraded to replace the red wood media with plastic media, replace the distribution arms, and install dispersion fans to reduce odor. Biosolids Lagoon 5 Renovation Project. Lagoon 5 will be divided into three lagoons designated as 5A, 5B and 5C (north to south). Lagoons 5A, 5B and 5C will process a mixture of primary and secondary sludge pumped from Lagoon 1. The capacities of the subdivided Lagoon 5 will be as follow: Lagoon 5A: 72,510,000 gallons, Lagoon 5B: 88,690,000 gallons and Lagoon 5C: 89,100,000 gallons. Maxson WWTF Administration Building. The existing administration building will be demolished, and a new 10,000 square foot administration building will be constructed, including a laboratory space, training rooms, parking for 65 vehicles, offices, conference room, locker rooms, electrical room, control and server room and reception area. Lagoon 2A Renovation. The existing 7 million-gallon Lagoon 2A will be cleaned out. This project will remove the top liner, dewater and dispose of the remaining material and re-cover Lagoon 2A. Repairs to the existing circulation pumps and/or biogas collector piping will also be addressed as needed during construction. Primary Clarifier Pumping. Clarifier 4 will be repurposed as a thickener to improve solids settling of the sludge from the primary clarifiers. A new large progressive cavity pump, with pump housing and associated piping, instrumentation and controls, will be designed and installed to pump the primary sludge from Clarifier 4 to the WWTPs sludge lagoons. This will replace the existing 6 smaller progressive cavity pumps that currently pump the sludge out of the primary clarifiers. Belt Filter Press (BFP) Improvements. Five 2-belt BFPs will be replaced with five 3-belt BFPs to increase the dewatering capacity and achieved dryness of the solids for disposal. This project also includes minor repairs to the existing building infrastructure. The T.E. Maxson WWTF Process and Biosolids Upgrades program is part of the City's capital improvement plan and will meet multiple objectives for the City of Memphis, including (1) satisfying new National Pollutant Discharge Elimination System (NPDES) permit requirements for effluent disinfection and reduction of total suspended solids and biologic oxygen demand, (2) improving biosolids treatment and processing capacity, efficiency, reliability, and flexibility, and (3) improving plant odor control.

EPA Region/Headquarters Office


State or Territory


Point of Contact

Alaina McCurdy

Date of Issuance


NEPA Document(s):

Memphis_NEPA CATEX_signed.pdf (6 pp, 1,558 K)